The invention relates to a labeling machine for objects, especially bottles, with several stations consecutively arranged along a path, namely, a gluing station, a label-supply station and a label-transfer station as well as at least one pickup element for the labels which is rotatably mounted on a revolving carrier and with each revolution of the carrier is moved past the stations, each such pickup element having an outwardly curved label receiving surface which rolls along the label which is foremost in each case, and along the other stations. With each pickup element is associated as a drive, a four-way toggle mechanism comprising a crank, a connecting rod and a swinging link. Two cam followers engaging the connecting rod are provided which are spaced a fixed distance apart and each of which is guided in a curved track cam path of its own which imparts to the pickup element a rotary motion with constant direction of rotation, the rotary motion being controlled by one of the followers when the other follower is in a dead position.
A labeling machine of this type is known from U.S. Pat. No. 4,077,621, particularly FIG. 8. In that labeling machine, the cam followers of the four-way toggle mechanism are disposed in such a way at the joints between the crank and the connecting rod on the one hand and connecting rod and swinging link on the other hand that the distance of one of the followers from the axis of rotation of the crank (of the pickup element) and the distance of the other follower from the axis of rotation of the swinging link are constant.
A complete revolution of the crank, and with it a complete rotation of the pickup element without reversal of direction, is achieved with the four-way toggle mechanism in that one of the curved track cam paths intersects the other curved track cam path or, respectively, that one of the curved track cam paths is formed only of curve segments. This means that one of the followers is only partly guided by the curved track cam path associated with it. The departure of that follower from the curved track cam path and its reintroduction into the curved track cam path is a drawback from the control standpoint since it entails increased wear. It would be preferable if the second follower, too, could constantly remain in its curved track cam path and the force necessary for the drive could be divided between the two followers.